Requirements:

Harvest 2'000 Bluebells
Harvest 30 Buddliea
Craft 12 National Park Signs
Rewards:
100 Gold Dust, Frontier National Park Sign, Flowery Ground Unlock
Notes: Bluebells are in the Market. Buddliea are a Free Gift. Signs are crafted.
Each Sign requires 6 Heavy Stones (Coal Piles) and 8 Carved Letters (Wall Post)